Preparatory pile used in the construction of concrete piles



INVENTOR P LANCSTER H. By" his At orneys,

LANCASTER Filed Jan. 29, 1923 mec. 18 1923.

PREPARATORY PILE USED IN' THE CONSTRUCTION oF CONCRETE PILES Patented Wee. 18, i923.

AHENRY PERCY LANCASTER, .OF LONDON, ENGLAND.

PREPABATORY PLEUUSED 1N 'THE CONSTRUCTEON OF .CONCRETE PILES.

Application fledi 'January `1923,.

To "all who/m,v t may conce/rn: i

Be it known that l, HENRY PERGY LAN- CASTER, a subject of the King of Great Britain, residing at 104 Victoria Street, London, England, have invented ce-rtain vnew and useful Improvements in Preparatory Piles Used in the Construction of Concrete Piles (for which I have filed application in Great Britain Dec. 3rd, 1921), of which the following is a specification. y

This invention relates to preparatory piles such as are used in the construction of concrete piles, and has for its object to ensure that the concrete pile is not of less diameter but preferably of greater diameter than that of the preparatory pile.

It has been found by long experience that in certain kinds of strata, for example peat and some kinds of clay, when the usual preparatory pile is withdrawn to permit the filling with concrete, the surrounding strata will press into the opening and result in the pile being of less diameter than the original preparatory pile. The finished pile is not only smaller than it should be in places but.is irregular in form. Furthermore, where the concrete is tamped by the reciprocatory movement of the preparatory pile, a certain amount of the earth surrounding the hole will fall into and mix with the outer portion of the concrete. My invention is particularly designed to prevent these objectionable results and to make it certain that the pile will be at least as large as the preparatory pile and of concrete unmixed with any foreign substances.

According to this invention to the preparatory pile are secured two collars, one to its lower end, and mounted upon the pile is a sleeve having a flange upon its internal upper end, which flange is capable of sliding between and is retained between the two collars on the pile, whilst the sleeveis large enough to pass over the lower of the collars. The lower collar is preferably provided with an inwardly projecting flange which extertigs beneath the bottom edge of the pile tu If desired the collars may be made in one piece with the pile tube.

The accompanying drawing shows sections of a pile made in accordance with this invention.

Figure 1 shows .a pile driven into the ground and a small quantity of concrete filled into the tube. Figurel 2 shows a pile collar and passing Serial No.l 615,606.

in which .the tube has vbeenwithdrawn short distance from the shoe and also a rammer for tamping the concrete. Figure 3 shows a pile in which the sleeve has also been raised from the shoe and in which the pile tube is used for tamping the concrete.

a is the tube of a preparatory pile having secured to it a collar b by rivets c and also a collar al by rivets e. On the collar Z) is a flange f which extends beneath the end of the tube a whereby the life of the tube is lengthened and repairs can be easily effected. Free to slide upon the tube a between the collars b and d is a sleeve g having a flange h whereby the sleeve is retained upon the tube a.

In operation the tube a and sleeve g rest upon a shoe y' and the pile is driven into the ground the required distance as shown in Figure 1. Concrete is now filled into the tube a which is then withdrawn a short distance as shown in Figure 2. The concrete then escapes from the tube and is engaged by the sleeve and is tamped by a rammer k thereby filling the sleeve with thoroughly compressed concrete which when the sleeve is withdrawn through the collar b engaging with the underside of the flange h forms a solid mass of concrete which will not be affected by the pressure of the ground and a concrete pile will be formed of larger diameter than the tube a which will not be distorted as to shape or squeezed to a less diameter than the tube as is often the case with piles as at present made.

Referring to Figure 3, it will be seen that the top ofthe collar b is below the bottom of the flange h of the sleeve g, as downward pressure has been applied to the tube a whereby the concrete is tamped by the tube itself. The tube is usually given an upand-down movement by which the sleeve g is slightly withdrawn on the upward stroke and the concrete tamped on the downward stroke. The sleeve may be of any desired length, the position of the collars being adjusted according to its length.

What I claim is 1. A preparatory pile, a collar at the lower end of the pile, a second collar on the pile spaced from the rst collar, a sleeve of a diameter greater than that of the first j thereover, and a flange on the sleeveA between the collars and of less diameter than either collar whereby the pile may' have a limited movement independentl of the sleeve. thus ensuring the production of a permanent pile larger vthan the preparatory pile.

2. A preparatory pile,v a Collar at the lower endV of the pile, a second collar on the .pile spaced ,from the first collar, a sleeve of a diameter greater than that of the first collar and passing thereover7 a flange on the j sleeve between the collars and of less diameter than either collar whereby the pile may have a limited movementindependent of the sleeve thus ensuring the production of a permanent pile larger than the preparatory pile, and a flange on the lower collar extending inwardly beneath the Vend of the-pile tube to protect the same. l

In testimonyV that 1I. `claim the .foregoing as my invention I have signed my name this 18th day of January, 14923.

HENRY PERCY LANCASTER. 

